The Extracranial Carotid Artery in Familial Hypercholesterolemia: Relationship of Intimal-Medial Thickness and Plaque Morphology with Plasma Lipids and Coronary Heart Disease

Background Increased frequency of coronary heart disease in familial hypercholesterolaemia is well documented but the association with carotid atherosclerosis is less well established. The ultrasound appearances of the carotid arteries in familial hypercholesterolaemia patients without symptomatic cerebrovascular disease were therefore investigated.

Methods 59 patients (34 men, 25 women; mean age 46.6 (± 12.1 years) were prospectively studied using ultrasound examination of the extracranial carotid vessels. Intimal-medial thickness was measured 1 cm proximal to the carotid bulb and morphology of plaque was classified as heterogeneous or homogeneous according to echogenicity.

Results 44 (75.0%) of the patients had carotid artery disease. On stepwise logistic regression, significant predictors of the presence of carotid artery disease were age (P = 0.014), serum triglycerides at time of examination (P = 0.013), coexistent coronary heart disease (P = 0.03) and the cholesterol-years score (CYS) (P = 0.015). Heterogeneous carotid plaque was associated with a higher plasma level of Lp(a) (P = 0.035), TG (P = 0.024), CYS (P = 0.0003) and the presence of CHD (P = 0.001). Matched pairs (n = 22) of patients, where the only variable was Lp(a), showed a marked increase in heterogeneous plaque frequency in those with high Lp(a) levels (P <0.03).

Conclusion Asymptomatic carotid artery disease occurs in a high proportion of familial hypercholesterolaemia patients. The presence of heterogeneous carotid plaque is significantly associated with the presence of coronary heart disease, the calculated cholesterol-years score, hypertriglyceridaemia and raised levels of Lp(a).